1. Field of the Invention
The present invention generally relates to internal combustion engines, and more particularly, to a sliding vane engine, wherein the vanes slide with either an axial or radial component of vane motion.
2. Description of the Related Art
The overall invention relates to the class of devices known as rotary vane internal combustion engines. These engines produce power through a sliding vane, positive displacement design whereby physically isolated volumetric compression and expansion occurs between the rotor, the sliding vanes, and the outer chamber casing. The vanes in such devices may have a radial motion, an axial motion, or a combination thereof, with respect to the rotor.
To date, vane designs have failed to detail a complete two-stroke design which can offer nearly twice the power-to-weight and power-to-size ratios without incurring significant pumping or throttling losses and which will operate in an efficient, reliable fashion.
Moreover, past vane engine designs have not suggested a means of allowing substantially higher efficiency without incurring the major costs of advanced, high-temperature structural materials, and without incurring differential thermal expansion difficulties related to the operating components.
Furthermore, past vane engine designs have not suggested a practical means of providing a variable compression ratio within a constant mass design. As used here, "constant mass" refers to a process which keeps the air and fuel volume predominantly within a given cell or chamber between two adjacent vanes throughout the cycle, without attempting to pump the mass to an entirely different chamber.
Also, applications requiring very large power output with minimal weight, such as commercial aviation engines, require a means to reduce the frictional power loss due to the reciprocation inertia of the vanes.
Finally, commercially available piston and Wankel rotary engine designs offer poor emissions performance and require catalytic converters to reduce emissions, and even with catalytic converters, pollutant output is substantially higher than desired, being on the order of several hundred to several thousand parts per million of NO.sub.x, CO, and HC for most applications. In addition, a major drawback of the use of catalytic converters is that their effectiveness weakens over time, requiring inspection and replacement to maintain performance.
In light of the foregoing, there exists a need for an adiabatic two-stroke vane design which would provide significant fuel efficiency, reduced emissions, and weight savings advantages. Moreover, a need exists for a constant mass, variable compression ratio vane design which would optimize fuel efficiency at all ambient conditions, thereby reducing fuel consumption, and also for a design which will minimize frictional power losses due to vane inertia, thereby allowing the sliding vane design to be competitive in a much larger class of engines.